The primary Aim of this study is to compare the effectiveness of the VCC, particularly the primary care component, with that of a traditional safety net delivery system at reducing the frequency of emergency department utilization, hospital utilization, and adverse health outcomes among uninsured patients who used the Virginia Commonwealth University Health System (VCUHS) from January 2003- December 2009, with attention to understanding the conditions and the types of patients for which the program was most effective. This will be achieved by a retrospective cohort study featuring three comparative analyses by cohorts: (1) comparison of utilization and adverse outcomes for VCC enrolees in the year after enrolment, versus the same patients during year prior to enrollment;(2) comparison of utilization and adverse outcomes for VCC enrolees versus simultaneous utilization and health outcomes of a similar uninsured population not enrolled in VCC, specifically patients classified as indigent and uninsured on VCUHS claims;(3) comparisons of utilization and adverse outcomes for VCC enrollees by the degree they engaged their assigned primary care provider. Analyses will be controlled for demographic characteristics and comorbidity. In addition, we will perform comparisons between PCMHs (group practices) within the VCC when the number of empanelled patients is large enough to permit statistically valid comparisons. Last, a secondary hypothesis will be explored by conducting separate analyses for patients with three of the MMedicare Modernization Act 14 priority conditions identified by AHRQ (pursuant to Section 1013 of the Medicare Prescription Drug Improvement and Modernization Act of 2003): cardiovascular disease, diabetes, and pulmonary disease/asthma. We chose these three conditions because each may require ED utilization, hospital or intensive care unit utilization, intubation, or result in death. The Secondary Aim of the study is to identify the successful and replicable elements of primary care case management, care coordination, and other attributes of the patient-centered primary care model that make the VCC program effective, with attention to understanding how and why these elements are critical for different patient populations. This will be achieved by qualitative analyses, consisting of key informant interviews and focus groups with four stakeholder groups: program executives/leadership, provider physicians, care coordinators, and patients, informed by results from previous work and from analyses performed under the first Aim. In addition, we will perform comparisons between practices providing PCMHs within the VCC when the number of empanelled patients is large enough to permit statistically valid comparisons. PUBLIC HEALTH RELEVANCE: The primary Aim of this study is to compare the effectiveness of the VCC, particularly the primary care component, with that of a traditional safety net delivery system at reducing the frequency of emergency department utilization, hospital utilization, and adverse health outcomes among uninsured patients who used the Virginia Commonwealth University Health System (VCUHS) from January 2003- December 2009. Attention will be paid to understanding the conditions and the types of patients for which the program was most effective. The Secondary Aim of the study is to identify the successful and replicable elements of primary care case management, care coordination, and other attributes of the patient-centered primary care model that make the VCC program effective. Attention will be paid to understanding how and why these elements are critical for different patient populations. This will be achieved by qualitative analyses, consisting of key informant interviews and focus groups with four stakeholder groups: program executives/leadership, provider physicians, care coordinators, and patients, informed by results from previous work and from analyses performed under the first Aim.